Pelargonium is a genus of flowering plants which includes about 200 species of perennial, succulent, and shrub plants, commonly known as geraniums. Confusingly, Geranium is the correct botanical name of the separate genus which contains the related Cranesbills. Both genera are in the Family Geraniaceae. Linnaeus originally included all the species in one genus, Geranium, but they were later separated into two genera by Charles L’Héritier in 1789. Gardeners sometimes refer to the members of Genus Pelargonium as "pelargoniums" in order to avoid the confusion, but the older common name "geranium" is still in regular use.
Other than grown for their beauty, species of Pelargonium such as P. graveolens are important in the perfume industry and are cultivated and distilled for its scent. Although scented Pelargonium exist which have smells of citrus, mint, or various fruits, the varieties with rose scents are most commercially important. Pelargonium distillates and absolutes, commonly known as "scented geranium oil" are sometimes used to supplement or adulterate expensive rose oils.
Pelargoniums are believed to deter mosquitoes.
Garden geranium (Pelargonium x hortorum; syn. Pelargonium zonale) is one of the most common ornamental potted-plants, with over 200 varieties.
In 1988 the flower was described and illustrated in a comprehensive 3-volume work Pelargoniums of Southern Africa by Ellaphie Ward-Hilhorst with van der Walt and Vorster.
Pelargonium leaves are usually alternate, and palmately lobed or pinnate, often on long stalks, and sometimes with light or dark patterns. The erect stems bear five-petaled flowers in umbel-like clusters called pseudoumbels. The shapes of the flowers have been bred to a variety ranging star-shaped to funnel-shaped, and colors include white, pink, red, orange-red, fuchsia to deep purple.
In early 2006 a long-awaited yellow-flowered variety was launched. Called the "Guernsey Flair", it was supplied exclusively to the television shopping channel QVC in the UK, and all available plants were sold within a few minutes. See photo of yellow geranium. The flower has a much yellower hue than the cream-colored varieties which some developers had called yellow previously.
Horticultural pelargoniums (as opposed to botanical, the wild 'species') fall into six major groups, with zonals subdivided further: